1. NASA Goddard Spaceflight Center; Greenbelt Maryland USA
2. Institute for Astrophysics and Computational Sciences; Catholic University of America; Washington District of Columbia USA
3. Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
4. Space Sciences Laboratory; University of California; Berkeley California USA
5. L'Institut de Recherche en Astrophysique et Planétologie; CNRS; Toulouse France
6. University Paul Sabatier; Toulouse France
7. Laboratory for Atmospheric and Space Physics; Boulder Colorado USA